Grassley in a letter sent on behalf of the Senate Judiciary Committee requested documents tied to Kavanaugh's work as a White House lawyer during the George W. Bush administration, but not tied to his work as staff secretary for the Bush White House.

Democrats on the Judiciary Committee immediately criticized Grassley's decision, which came after days of rhetorical firefighting and a flurry of letters between senators.

Democrats argue documents from Kavanaugh's time as staff secretary are crucial for understanding his thinking on some of the most controversial policies of the Bush administration, including torture and surveillance.

But Republicans had dismissed their broader request as a "fishing expedition," and characterized Kavanaugh's work as a staff secretary as a "paper pusher" that would shed little light on his judicial philosophy.

"I expect the production to be the largest ever in the Senate’s consideration of a Supreme Court nominee. ... As I have said repeatedly, I am not going to put the American taxpayers on the hook for the Senate Democrats’ fishing expedition," Grassley said in a statement.

"I’ve found myself either waiting for a response to my proposals or faced with unprecedented and unreasonable counter-proposals," he said.

He added that Democrats want a "search of every email from every one of the hundreds of White House staffers who served alongside Judge Kavanaugh for nearly six years, to find records that merely mention his name."

Grassley's decision could limit Democrats' ability to get documents from Kavanaugh's work as staff secretary.

The National Archives in a letter to Feinstein said that a committee's power to request documents under the Presidential Records Act rests with a panel’s chairmen, who are all Republicans.

But Feinstein fired back in a letter to the agency released on Friday that they have to respond to requests from both Republicans and Democrats.

“Your unduly restrictive reading of the law results in one political party having complete control over what records the Senate will be able to see,” she wrote, adding that “a biased denial of document requests to one half of the Committee is unsupported by the law.”